Electrode for vacuum tubes



July i929. D. A. MULLANEY Er Ai. L7219405 ELECTRODE FOR VACUUM TUBESFiled July 8, 1925 A w f,

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i U o T DJ Patented July 16, 1929.

UNITED STATES 1,721,405 PATENT OFFICE.

DUDLEY A. MULLANEY AND JOHNSON F. HENDRY, F SCHENECTADY, NEW YORK, 'i

ASSIGNORS TO GEN EBALELECTRIO COMPANY, A. CORPORATION 0F NEW YORK.

ELECTRODE FOR VACUUM TUBES.

v application 111mlv mi a, 1925. serial No. 42,274.

Our invention relates to improvements in electrodes for vacuum tubes,and more particularly to methods of constructmg and supporting the gridsand anodes used 1n such 5 devices.

It is the object of our invention to provlde an electrode structurewhich shall notonly be light and rigid but the parts of whlch will besymmetrical and consequently adapted for rapid assembly in jigs, andfixtures so as to reduce manual assembling operations to a minimum. i

In the manufacture of anodes and grlds for space current devices,particularly of the t-ype known as power tubes 1n which the electrodesare of considerable size, it 1s customary to use heavy rods ofAmolybdenum or tungsten for supporting the electrodes. These are usuallyriveted to the electrode body itself and either welded or riveted tometal straps by means of which the assembled structure 1s clamped tosome lass member of the tube,

usually the stem t rough which the lead-in wires pass. D

In accordance w1th our 1nvent1on we use a lighter but equally rigidstructure for uniting the parts Vof such electrodes as well as forholding the samev in position in the tubes.

The structure is shown in detail in the annexed drawing in which:

Fig. 1 shows ourl improved supportmg structure as applied to an anode ofa space current device.

Fig. 2 illustrates this applicatlon to a grld or control electrode, and

Fig. 3k depicts a complete space current device embodying the improvedelectrode of our invention whi e Fig. 4 is a detail of an anode.

The improved structure of the invention is applicable to different typesof electrodes so that both anode and grid may, for example, be builtalon the same general lines.

Referring 1n detail to the drawings it will be observed that the anodesupport of Fig. 1 is made from flanged or channel members 1,-2,preferably rolled or stamped from sheet molybdenum or other suitablemetal. These are attached to the anode sections, preferably by rivetingalthough they may be spot welded in place if desired. Each channelmember has welded or riveted to it at the end opposite the anodeone-half 5 or 6 of a metal clamp. The two halves when placed togetherare adapted to embrace the glass stem 30 or 34 of the tube ina mannershown in Fig. 3 where a portlon of such a clamp is visible. `For thispurpose, the clamps are provided with holes 7, 8, 9, 10 for thereception of screws which are indicated in Fig. 3.

Fig. 4 illustrates a detail of the anode y structure showing -a methodof constructing the anode in question'so as to secure substantiallythesame bracing effects of the channel members 1 and 2 and thus additionalstrength. In this case, the anode is composed of flat members 3, 4, 11,12 provided with flanges 13 by means of which the members 1 may beassembled by riveting or welding as desired.

Fig. `2 illustrates the application of the channel supports to theconstruction of a grid or control electrode. In this case the flanged orchannel members are represented by 14, 15. These are attached to clampmembers 5 and 6 in the same manner as the anode of Fig. 1, the clamps inthis case serving the same purplose heretofore 'described for the anode.

T e gridwire 17 is wound over the channel members, the latter being wideenough so that the resulting cage will accommodate the filament orcathode which is shown at 18. The upper portions 'of the channel members14, 15, are held together by means of bar 19 made of suitable insulatingmaterial such as fused quartz which is embraced and held by theends ofthe channel members in any appropriate way. This bar serves as a supportfor the cathode and wires 20 may be imbedded in the quartz and used tohold the cathode supporting system which comprises insulating members 21preferably made of fused quartz, spring 22 and retaining hooks 23. f

Other metal supporting members may be held by the quartz cross-piece 19to aid in keepin the elements of the tube rigid. Thus, the en 24 of theleading-in conductor 32 which is sealed into the press 25 may extendbeyond the press and rest in a bearing hole in the quartz bar 19. Thisfacilitates assembly since the anode and cathode may be rapidly andaccurately brought into their relative juxtaposition and rigidly held inplace.

A conductor 33 may be wrapped around the wire 32 in any suitable mannerand attached to one of the electrodes of the device, for example, theanode, and thus serve to connect the anode with the terminal 27.

Figure 3 shows the method by which the electrode and supports aredisposed in a 11o s ace current device of the power tube type.

he tube consists of a glass container 26 a A portion of which is shownbroken away. The anode 11 is also shown broken away in order to exposethe rid and cathode whose structure has been escribed in detail above.The

-cathode leading-in wires are indicated by 31, embedded in aA lass pressaround which is clamped the gri support composed of clamp members 5, 6.The'lament conduc-K tors are brought out to terminal posts only one ofwhich, 29, is shown, while the grid is connected to ost 28 whichtogether with bers of which only system described above is very rigid,easily reduced and readily assembled. 1t is less iableto warp out ofshape under the stresses produced by the heat evolved during theoperation of the tube and presents the further advantage ofbeingadaptable to quantity manufacture and assembly in machines and 310s.

bWhat we claim as newand desire to secure by Letters Patent of theUnitedStates, 1s:-

. 1. A space current device comprising a container of insulatingmaterial, a reentrant glass tube at each end of s aid container, anVanode mounted on one of said reentrant tubes and a grid mounted on theother reentrant tube,rthe su ports of both anode and grid comprisinganged members metallically attached to and extending along the entire1ongitudinal axis of the surface of said anode and grid, said anode andgrid being provided with clamp members adapted when coacting with eachother to embrace said respective reentrant glass tubes.

2. In a space current device, an anode com'- prising a plurality ofalternately arranged iat and round ortions provided with flanges whichextend 1n a direction normal to the surfaces of said portions at theiredges, said flanges being secured together to form a rigid body ofclosed perimeter, and means for supporting the anode within the device,said means comprising a pair of oppositely disposed channel memberssecured to said flat anode portions.

3. In a s ace current device, a grid comprising a pllilrality ofuprightchannel members about which the grid wire is Wound, a clamp secured toone end of the channel members for supporting the grid within thedevice, .the opposite end of said members being spaced by an insulatingmaterial which is adapted to constitute an electrode support.

4. 1n a space current device, an evacuated envelope provided with areentrant stem a combined filament and grid electrode arrangementcomprising a pair of upright channel members about which the grid wireis wound, said members being spaced by au linsulating material at oneend and terminating in a clamp at the other end which embraces saidstem, a filament suspended between the insulating material' and saidstem. Inwitness whereof,;we have hereunto set our hands this 7th day ofJuly, 1925.

' -DUDLEY A. MULLANEY.

JOHNSON F. HENDRY.'

